Control device for vehicle

Abstract

A control device for a vehicle includes a failure detector to detect failure in a cooling device to cool an internal combustion engine of the vehicle. An acceleration operation sensor is to detect an acceleration operation amount indicating a target acceleration. Circuitry is configured to control a power output from the internal combustion engine in accordance with the acceleration operation amount, control an air fuel ratio of air-fuel mixture in the internal combustion engine to be in a richer side with respect to a predetermined air fuel ratio if the acceleration operation amount exceeds a high load threshold, limit the power output from the internal combustion engine if the failure detector detects the failure, and prohibit the air fuel ratio from being controlled to be in the richer side even if the acceleration operation amount exceeds the high load threshold if the failure detector detects the failure.

What is claimed is: 
     
       1. A control device for a vehicle which is driven by an internal combustion engine and provided with a cooling device for cooling the internal combustion engine, comprising:
 a failure detection means for detecting failure of the cooling device; 
 an acceleration operation amount detection means for detecting an acceleration operation amount indicating acceleration intention of a driver; and 
 an output control means for controlling an output of the internal combustion engine in accordance with the acceleration operation amount, 
 wherein the output control means has an air fuel ratio control means for controlling an air fuel ratio of air-fuel mixture which is burned in the internal combustion engine, and wherein, in a condition in which the failure of the cooling device is detected by the failure detection means, the output control means restrains output of the internal combustion engine and executes failure handling control for prohibiting the air fuel ratio from being controlled to a richer side with respect to a predetermined air fuel ratio when the acceleration operation amount exceeds a high load determination operation amount. 
 
     
     
       2. A control device for a vehicle according to  claim 1 , further comprising an engine temperature parameter detection means for detecting an engine temperature parameter which is correlated with a temperature of the internal combustion engine, wherein the output control means does not execute the failure handling control when the detected engine temperature parameter is lower than a predetermined temperature in the condition in which the failure of the cooling device is detected. 
     
     
       3. A control device for a vehicle according to  claim 1 , wherein the cooling device is arranged in an engine room in which the internal combustion engine is accommodated and comprises a grill shutter for adjusting an amount of air which is introduced in order to cool the internal combustion engine. 
     
     
       4. A control device for a vehicle according to  claim 3 , wherein the failure detection means detects such closing failure that an opening degree of the grill shutter is located on a closing side with respect to a command opening degree. 
     
     
       5. A control device for a vehicle according to  claim 1 , wherein the predetermined air fuel ratio is a theoretical air fuel ratio. 
     
     
       6. A control device for a vehicle, comprising:
 a failure detector to detect failure in a cooling device to cool an internal combustion engine of the vehicle; 
 an acceleration operation sensor to detect an acceleration operation amount indicating a target acceleration input by a driver; and 
 circuitry configured to
 control a power output from the internal combustion engine in accordance with the acceleration operation amount, 
 control an air fuel ratio of air-fuel mixture in the internal combustion engine to be in a richer side with respect to a predetermined air fuel ratio if the acceleration operation amount exceeds a high load threshold, 
 limit the power output from the internal combustion engine if the failure detector detects the failure, and 
 prohibit the air fuel ratio from being controlled to be in the richer side even if the acceleration operation amount exceeds the high load threshold if the failure detector detects the failure. 
 
 
     
     
       7. The control device according to  claim 1 , wherein controlling the air fuel ratio to be in the richer side includes controlling the air fuel ratio to be less than the predetermined air fuel ratio. 
     
     
       8. A control device according to  claim 6 , further comprising an engine temperature sensor to detect an engine temperature parameter corresponding to a temperature of the internal combustion engine, wherein the circuitry does not prohibit from controlling the air fuel ratio when the engine temperature parameter detected is lower than a predetermined temperature if failure detector detects the failure. 
     
     
       9. A control device for a vehicle according to  claim 6 , wherein the cooling device is arranged in an engine room in which the internal combustion engine is accommodated and comprises a grill shutter to adjust an amount of air to be introduced in order to cool the internal combustion engine. 
     
     
       10. A control device for a vehicle according to  claim 9 , wherein the failure detector detects a failure of closing in which an opening degree of the grill shutter is smaller than an opening degree in which the grill shutter is controlled to open. 
     
     
       11. A control device for a vehicle according to  claim 6 , wherein the predetermined air fuel ratio is a theoretical air fuel ratio. 
     
     
       12. A control method for a vehicle, comprising:
 detecting failure of a cooling device to cool an internal combustion engine in the vehicle; 
 detecting an acceleration operation amount indicating a target acceleration input by a driver; 
 controlling a power output from the internal combustion engine in accordance with the acceleration operation amount; 
 control an air fuel ratio of air-fuel mixture in the internal combustion engine to be in a richer side with respect to a predetermined air fuel ratio if the acceleration operation amount exceeds a high load threshold; 
 limiting the power output from the internal combustion engine if the failure detector detects the failure; and 
 prohibiting the air fuel ratio from being controlled to be in the richer side even if the acceleration operation amount exceeds the high load threshold if the failure detector detects the failure.